Method of and apparatus for regulating electric circuits



5 Sheets-Sheet I.

(No Model.)

J. M BRADFORD. METHOD OF AND APPARATUS FOR REGULATING ELECTRIC CIRCUITS.

Pat efited Mar. 5, 1895.

(No ModeL) 5 Sheets-Sheet 2. J. M. BRADFORD.

METHOD OF AND APPA No. 535,158.

RATUS FOR REGULATING ELECTRIC CIRCUITS.

Patented Mar. 5, 1895.

m, E55: E55:

(No Model.)

Q 5 Sheets-Sheet a. J. M. BRADFORD.

METHOD QF AND APPARATUS FOR REGULATING ELECTRIC GIRGUITS. No. 535,158.

Patented Mar. 5, 1895.

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S l 3 R 19 .Ec l a /J\ WITNESSES: INVENTOH: ZLA 1 v 5 Sheets-Sheet 4.

(No Model.)

J. M. BRADFORD. RATUS FOR REGULATING ELECTRIC CIRCUITS.

METHOD OF AND APPA No. 535,158.

Patented Mar. 5, 1895.

e %Wmnv (No Model.) 5 SheetsSheet 5.

J. M. BRADFORD. METHOD OF AND APPARATUS FOR REGULATING ELECTRIC CIRCUITS.

No. 535,158. Patented Mar. 5, 1895.

WITNESSES: ||\l\/El\l z mvmns Incas 0a.. rncmuruo wAsulNcmM. o c.

UNITED STATES JULIEN M. BRADFORD,

PATENT OFFICE.

OF PORTLAND, MAINE.

METHOD OF AND APPARATUS FOR REGULATING ELECTRIC CIRCUITS.

SPECIFICATION forming part of Letters Patent No. 535,158, dated March 5, 1895.

Application filei Tannery 9. 1894- Serlal No. 496.303. (No model.)

3'0 all whom it may concern..-

Be it known that I, JULIEN M. BRADFORD, acitizen of the United States, residing at Portland, in the county of Cumberland and State of Maine, have invented a new and useful Method of and Apparatus for Regulating Electric Circuits, which is described -in the following specification with suflicient clearness toenable others skilled in the art to which it appertains to make and use the same.

My invention relates to systems of electrical distribution; and the purpose thereof is to provide automatic means whereby the current upon circuits may be regulated and maintained at a certain degree, or at a substantially uniform intensity.

The invention described in-the following specification is.widely applicable to different systems of generating and distributing electric currents, being especially intended for use at electric lighting and power stations, to aid in the economic generation and distribution of curreut,-thereby securing the various advantages incident to proper regulation.

This invention provides means to govern the speed of engines supplying power.

Dynamos with compound winding for selfregulation must bedriven at apredetermined rate ofspeed in enter to give the required resnlts. The following specification describes apparatus to govern the speed of such dynamos by governing the speed of the engines by which they are driven.

The salient features of the following de scribed apparatus include-- First. A current-varying device or commutator,designed to control the current of electricity, steam or other force producing agent requiring regulation: The current-varying device acts in one direction to increase, in the opposite direction to decrease the current which it controls. to be progressive and retrogressive.

Second. The driving power: This power actuates the current-varying device and is derived from any convenient source, such as the engine driving the dynamo, or from a small electric motor. It is constantly expended in excess of requirements and is utilized in proportion to the extent-and frequency of movements of the current-varying device. It may be called a dilferential power since it This action may be said.

is expended in one direction or the reverse with. dilferent. efiect.

Third. The controlling power: This power governs the action of the driving-power above mentioned. It is produced by an electric current which alternates, or acts by turns, simultaneously releasing and causing movement of the current-varying device, or by reverse of such action preventing movement of said device. This also may be called a differential power since it is expended in one direction and the reverse with ditferentefiect.

Fourth. The stop-motion device: This device is operated by the controllin -power above mentioned and acts asaspecial means to aid in holding the currentvarying device stationary while the current to be regulated is of normal force.

Fifth. Controllers: These devices govern the action-of the controlling powerabove mentioned. They include devices responsive to variations of electric current, also to variations of engine speed and Figure 15 shows a device to limit the movement of the currentvarying device. When these controlling de-- vices break a circuit the neutralizing effect of sudden increase of the opposite acting current has tendency to prevent injurious sparks. By the arrangement shown in Fig. 17 the current is not broken, butthrowu into waves of varying force. Thecontrollers with two levers 42 are designed to preventinjurious oscillations, or to secure more nearly a deadbeat action. By the arrangement shown in Fig. 7 the action of lever 42 breaks one contact and makes anew contact at substantially the same instant, thereby preventing wheel 16 from being acted upon oppositely at the same time.

Sixth. The arrangement for independently operating several-regulators by one motor:

This apparatus may be used to regulate circuits for constant current, or for constant electro-motive force, according to the arrangement and requi ernentsin ditfereutcases. To

check, anticipa e, or prevent, by the use of auxiliary power material development of incipient faults in the current to be regulated, is a prominent feature of this invention.

Of the drawings illustrating this invention, Fig. 1 is a front view of the regulating apparatus. Fig. 2 is a section of Fig.1. Fig.3

is a plan of Fig. 1. Fig. 4 isadiagram showing an application of the apparatus to a series dynamo. Fig. 5 is a diagram, showing a different form of regulating apparatus applied to a series dynamo. Fig. 6 is a side view of an electric controllen Fig. 7 is a side view of another form ofelectric contrcller. Fig. 8 is a side view of a rheostnt'. Fig, 9isadiagram showing a mode of applying ditferential winding to an electric controller. Fig. 10is a diagram showinga mode of workiugsev l regulators by one power shaft. view of a different form of regulating apparatus, also with a controller attaohed. Fig. 13 is a plan of Fig. 11. Fig. 13 i's a diagram showing an application of .the apparatus toa series dynamo. Fig. 14 is adia'gram showing the apparatus arranged to govern the speed of an engine. Fig. 15 showsthe apparatus illustrated by'Fig. 14 with the addition of a break circuit device to limit the movement of the regulating valve. Fig? 16 is adiagramiof another form of speed governing apparatus. Fig. 17 is a side view of a spe'edcontroller arranged .to throw the electric current intm waves of varying force. Figs. 18 and 19 are different forms of speed governors. Fig. 20 is a side view showing a. mode attaching the speed governing apparatus to the throttle valve of an engine. Fig. 21 is a plan showing a mode of attaching the speed governing apparatus to an engine with variable cut-o'tf. Fig. 22 is a detail of Fig. 21. Fig. 23 is a plan showing a mode of attaching the speed gov erning apparatus to another form of engine with variable cut-off. Fig. 24 is'a side vi ew of'adetuilofFigz23q. v

Figs. 1, 2,5 and 4 show a construction of the apparatus'and its application to a series dynamo. The electro-magnets 15 are each encircled by coils A and B wound in opposite directions foropposite magnetic effect. Each magnet 15 is armed with a spur gear G and loosely supported upon shaft 4. .The gears G engage with pinions P attached to shafts S and ll. Upon the ends of shafts S and II are fixed the beveled gearsb'b engaging with a third beveled geart fixed upon shaft J. The pulley 5, (Fig. 4) may be fixed to shafts or to shaft J or Ii according to convenience. Power being applied to either of theabove named shafts will cause magnets 15 to revolve in opposite directions. Between magnets 15 is placed wheel ltkafixed to shaft 4,wvhich is supported by bearings D D. Wheel 16 may be made hollow for lightness, in order that the resistance which it offersto sudden starting and stopping may be small.

Magnets 15 are so adjusted upon shaft 4 that; they remain very close to the sides of wheel 16', or for greater quickness of action they may be caused to remain in constant contact with wheel 16 by light pressure of elastic washers E E.

Connection s made between the brushshifting yoke Y of the dynamo and wheel 16 bymcans of shaft 4, crank C and rod R.

Fig. 11 is a front In practice an adjustable crank C (Fig. 13)

may be used in order that. different degrees of movement of the brushes may be obtained by connecting'rod R to different parts of the crank.

The stop-motion device consists of a brass spool M inclosing a movable iron core K. The spool M is encircled by coils O, and L wound in opposite directions for opposite magnetic ettecn. In practice several stop-motion devices may be usedfor increased cfiect, arranged asshown in Figs. 1 and 3 and alloperated by the same cont-rolling circuits.

The main current'flows from the dynamo by wire .3, thence through coils 48 of thefcontroller to bindingpost 7 electricallyconnected with the two levers 42 and also with the binding-p'ost 8, thence by wire 9 through'coil A, thence through coil 0 of the stop motion dev ice,-theuce thr'oughthc coil encircling wheel 16,- thence tlirough coil'A to binding-post 10,

- thence through the frame of apparatus to the 1 81 pole of dynamo by way of wire attached to binding-post 12.

-The above described current flows in a direction to impart to the sides of wheel 16, and

,the ends of magnets 15- facing the sides of said wheel ,the'satn'e magnetic polarity. In other words, one side of wheel 16 will be positively magnetic, and theend of the magnet 15 facing tliat side will alsobe positively magnetic. The opposite side of wheel 16 will be negatively magnetic, and the endof the magnet: ldfacin g that side will also be negatively magnetic. This similarity of magnetic polar-- ity causes repulsion between wheel 16 and magnets '15. The above described current,

-however, flows in a. direction through coil 0 of the stopmotion device to cause the polarity of the lower end of core K to be opposite to thepolurityot the end of wheel 16 upon which it rests, thereby causing said wheelto be held stationary by magnetic attraction. The brushes of the dynamo connected to wheel 16 consequently remain stationary whilethe current flows in the manner above described.

It the main-currentincreases beyond the required degree, the right hand lever 42 is lifted into contact with screw 46, causing a current to flow from wire 18 through coil B, thence through coil L of the stop motion de- 4 vice, thence to biuding-post14,thence through frame of apparatus to other pole of the dynamo by wire attached to binding-post 1:2. The instant lever 42 touches screw 46 the current is divided. The circuit by way of wire 13 receives one half of the current, and the circuit by way of wire 9 the other halt.

The current from wire 13 reverses the polarity of right hand magnet 15 and also reverses the polarity of core K of the stopmotion device, by reason of coils B and L each having a greater number of turns than coils A and O, causingmagnet 15 to grasp and core K- to release wheel 16. By the grasp of revolving magnet 15, wheel 16 with brushes of dynamo attached are moved sutficientlv to cause the grasp and magnet 15 to release wheel 16 by change'of magnetic polarity; This instantly arrests motion of wheel -1 6,and brushes of dy- -namo. If the main-current falls'below the zo-main-current.

required degree, the left hand lever 42 falls in contact with screw 45,causin g a current to flow through wire 17 to coil B, thence through coil Lof the stop-motion device, thence to bindingpost 14, thence through frame of apparatus to other pole of the dynamo by wire attached to binding-post 12. This current causes core K to release, and the left hand magnet 15 to grasp and move wheel 16 with brushes ofdynamo in the opposite direction to increase the The instant the main-current gains-suflioient strength to lift lever 42 from screw 45, the circuit by way of wire .17 is broken,c ausing current from wire 9 to double in strength and motion of wheel 16 with brushes of dynamo tobe arrested by destruction of magnetic attraction of left hand magnet 15 and graspof coreK of the stop-motion device, as before described.

Coils A and O neutralize magnetism at the instant a lever 42 breaks contact with screw or 46. This arrangement -hae tendency to prevent sparks. If aldditiqnaifmeans are required for this purpose conductors of high resistance may b used to connect screws 45 and 46 with binning-post 7.

, A modified form of apparatus is shown in Fig. 5- Bil-his arrangement .the main-currentiiows' from the'dynamo by wire 3, thence through coils 43 of the controller tobindingpost 7, thence from binding-post 8 to coil 0 of the stop-motion device, thence through the coil encircling wheel 16, thence through coil A, thence t'o'binding-post It), thence through frame of the apparatus to other pole of dyname by wire attached to binding-post 12. This current causes magnetic attraction between core K of the stop-motion .deviceand wheel 16, also prevents attraction between 'wheell6 and. magnet 15, thereby preventing movement of wheel 16 with brush of dynamo attached as previously fully described.

If the main-current increases'beyond the required degree, right hand lever 42 is lifted into contact with screw 46, causing a current to flow from wire 13 through coil B, thence through. coil L of the stop-motion device, thence to binding-post 14. Thiscnrrentcausi-s thestop-motioudevice to release wheel 16 and revolving magnet 15 to grasp and move said wheel, thereby reducing the main-current in the manner previously fully described.

If'the main-cu rrent falls below the required degree, left hand lever 42 falls in contact with screw 45, causing a current to flow through wire 17 to coil L of the stop-motion device, thence to binding-post 14 and thence to the other pole of dynamo by way of frame of ap'' paratns and wire attached to binding-post 12. This on rrent causes the stopmotion device to release wheel 16 and weight 18 to move said wheel in the opposite direction .to' increase the'main-current. The instant the main-current gains sufficient strength to lift left hand lever 42-from screw 45, the current through wire 17 is broken, causing current from wire 9 to double in strength and the motion .of' wheel 16 to be arrestedby grasp of the stopmotion device as before described.

The current controller is adjusted in the following ma'n'ner':The main-current flowing through right hand coil 43 produces magnetism which has tendency to lift right hand lever 42 into contact with screw 46; If an electrical pressure of twothousnnd v'oltsis required to cause snhicient current. to. flow through the main-circuit, weight .Ngis so'adjust that lever 42 will not be lifted into contacmit-h screw 46 while the current does not exceed that degree of pressure. 'If the current exceeds two thousand volts, lever 42 isilifted into contact with screw 46, thereby completing circuit-and causing the regulating apparatus to reduce the current as before explained. -The weight T on left hand lever 42 is so adjusted that a current of a little less thantwo thousand volts is sufl'icien't to prevent said lever from falling into contact with screw 45. If that current falls much below two thousand volts lever 42 falls into contact with screw 45, thereby completing a circuit and causing the regulating KOO apparatus to increase the current as before explained. By this arrangement the voltage of the main-current is increased or diminished by increasingor diminishing the .weight on the right hand lever 42. The weight on the left hand lever should be less than that on the right hand lever. This difference of weight, which maybe increased or diminished at will, determines the iimito'f variation which may take place in the main-current without cans-' ing a circuit to be closed .by movement of a lever 42.

The controller Fig. 6 with one lever 42 may be used instead of the double lever controller last described. In this arrangement onelever 42 makes and breaks both circuits, the midway. position of the lever being determined by the magnetic power'of coil 43 actingin opposition to the traction of the weight. This arrangem'en t, commendable on the ground of simplicity of construction, has, however, tendency to disturb action of the apparatus by lever 42 oscillating between screws 45 and'46, instead of maintaining a'midway' position while the main-current is substa tialiyof the right force. The magnetic power of coil 43 which lifts lever 42 out'of coutactwith screw 45, has also tendency to throw it'into contact with screw 46. .Also the weight which draws lever 42 out of contact with screw 46, has

.tendency to throwit into contact with screw 45; When two levers 42 are used, each lever v makesandbreaksbutonecircuit. Therefore the liability of a lever closing the opposite circuit by excess of movement is avoided.

. By the controller shown in Figst4 and' 5 both circuits by the way of screws and 46 might accidentally be closed at once, thereby causing magnets 15 to act oppositely at the same time. Such action might result from improper adjustment of weights N and T or from other cause. If a controller. is required which is not subject to such action, thearrangeinent shown inFig. 7 may be adopted. By this arrangement-current flows through coils 43 to binding-post 8,- thence'to levers 42 by themetallicstrip 47 which is in contact with the levers at 48 and 49. A movement of the right hand lever 42 completes a circuit by way of screw 4.6, and a movement of left hand lever 42 completes a circuit byway of screw 45, but'lf bothlevers 42 move at the same time, contact between them and metallic strip 47 is broken and neither of .the above described circuits can receive current.

Besides the application to the brushes of a dynamo the apparatus is well adapted to operate a rheostat'to regulate the field'current of a shunt-wound dynamo, or for other purposes. The arm of the rheostat (Fig. 8) may be fixedto shaft 4 of the apparatus which is regulated by a controller suitably connected with the main-circuit. In feeding incandescent lamps, in parallel the electr c-motive force-is, when many lam s are burning, higher at the poles of the dynamo than at remote parts of the circuit- To cause the apparatus to maintain a current of suitable electro-motive force at a distance from the generator, the-controller ,may be differ- -entially wound, asshowu in the.diagra'm Fig. 9. Bythisarrangement a' part of-coils 43 are wound with coarse wire'through which flows a direct current, anda small current is caused "to jflow it; the opposite direction through the hue wire coils fed by the main cqnductors'in the manner shown in the'diagram. The number of turns of wire in both coarse and fine wire coilsare adjusted to produce the required relative effect. While but little current is used in the main-circuit but little current flows through the coarse'c'oils. Therefore the effect produced by current through fine coils is but'slightly reduced. As

more current flows through coarse coils to supply increased demand the etfect .of current through fine coils is proportionally counteracted. V v

ln extensive systems many rheostats are often required, all of which may be operated by apparatus-driven by one o'wer-shaftas shown in the diagramfiig. 1 I By this arraugement eight magnets 15 are driven by onepower-shaft S. The fQlH WhQGlS 16,,(Fig. 4,) operated by these magnets act-independently'of each other bysreason of being governed by controllers operated by ditfe'rentcircults.

Regulating apparatus dilfering in several Bythis arrange:

in showing the electrical-connections but-one" magnet is shown in-Fig. 13. ;One end of coils A B encircling magnet 15 is connected to metallic rings h k insulated from each 0 her and also'from the hub of gear G to which hey are attached. The'brusbes d f rest in contact with rings h k. WeightlB imparts to wheel 16a constant tendency to move in a direction ppposite to that imparted to said wheel by the adhesion of revolving magnet 15. The rod'B. crank C with the yoke Y brushes of the dynamo.

also be attached to crank tion. The main-current flows from one pole of the dynamo through wire 3 to coil 43, thence to binding-post 8, thence through wire!) to brush f, thence to ring It, thence through coils Ato gear G, thence through frame of the apparatus to binding-post 12, attached to the other pole of the dynamo. This strong current causes magnet 15 to adhere to and move wheel 16 with brushes of dynamo attached in the right direction to reduce the main current. The in- A dash pct 19 may stant the main current is reduced sufliciently to allow lever 42 to fall upon screw 45 o'ne half of said current flows through wire .17 to brush (1, thence to collar k, thence -to coil Band thence to the other pole of the dynamo as before described. The current in coil B reverses polarity of magnet 15 and.the.opposite action of coils A and Breduces magnet- C to steady its mo-1 connects for'shifting' the v ism sutliciently to allowweight 18 to'move wheel"16 and brushes of dynamo in the opposite direction to increase the main current.

The instant the main current gains sutficient strength to lift lever 42 from screw 45 coil is released from action by rupture OfCllOlllt I by way of wire 17 and atzthe same'instant the current in coil Adoubles in strength thereby again reversing polarity of magnet 1511\ndcausing said magnetto adhere to and move wheel 16 with brushes of dynamo as before described. By this arrangement the coil ehcircling wheel 16 has been omitted. Magnet 15 and wheel 16 do not repel each other exceptin g at the instant lever 42 closes or breaks contact with screw 45. The end of magnet 15 in contact with wheel 16 may be covered with a thin plate of brass to lessen the friction caused by the-poles of said magnet slipping upon the surface of wheel 10 when the magnetism is reduced to allow weight 18 to move the wheel in this manner. SVeight T of the controller is so adjusted that lever 42' will not break contact with screw 45 until the main-current slightly exceeds the required degree. v

lYhile the main-current is substantially of posts V and F representing the source fromright quantity, the alternations of current through coils A and B of magnet 15 neutralize each other, and little or no movement of wheel 16 results. '15 there is'au excess or deficiency of that current lever 42 breaks'orcloses cir-' cuit for a longer time, causing wheel 16 and brushes of dynamo attached to move in the right direction to correct the fault.

Fig; 14 shows an arrangement oi the apparatus forgoverniug the speed of engines. The

speed controller, or governor as it s commonly called, is driven by connecting p'nlley Z to the engine to be governed; The adj ustmentis such that. lever 42remains' midway between screws 45 and 46 while the speed of engine is normal. The current to control;

thi'ssp'eed regulating apparatus istaken from any convenientsource of supply, the bindingwhich it flows to the 'apparatus. The valve for controlling the steam driving the engine is attached to shaft 4 in the manner hereinafter described. Shaft S is connected to the engine to be governed. by means of gearing, or the belt and pulley previously described maybe used for this purpose. While the speed of the engine is normal, lever 42 is midway between screws 45 and 46 causing current to flow from binding-post F to wire 9, thence through coils of apparatus and back to the other pole of the circuit .at- V. This current causes wheel 16 to be held stationary as before fully explained' Iffspeed of the engine declines or increases, a circuit isclosed by way of screw 45 or-46, instantly causing a movement o'fwheel 16 as before explained; and thereby regulating speed of the engine by movement of valve attached to the shaft of said wheel. As soonas normal speed of engine is restored, lever 42 returns to midway position. between screws 45 and 46, causing current from wire 9 to double in strength and wheel 16 to be held stationary as before ex plained.

The apparatus shown in Fig. 15 is thesame as that shown in Fig. 14, save in the addition of a device to break circuits and thereby stop the motion of shaft 4when the speed regulating valve attached thereto has moved to its extreme limit. either in opening or closing. This device consists of a rod 111. eccentri'cally attached to shaft 4. Two collars pand w are fixed to and insulated from rod m. The speed regulating valve which is opened and closed by movement of shaft 4 should be so adjusted that it will be fully closed when rod m is moved downward to its lower limit as shown in the figure.

If lever 42 of the speed controller momentarily remains in contact with screw 46 after the speed regulating valve is fully closed, motion of said valve is stopped by wire 13 slipping oil 01? collar 1). On the other hand the instant the speed regulating valve is fullythrough lever 42 and wire 18 to coil B'encircling magnet 15, thence through tfra'me of ap-. paratus to binding-post 1 3 and thence to'binding-pos't V. This current causes revolving magnet 15 to'grasp and move wheel 16 with valve attached to shaft 4 inth right direction to reduce speed of the engine The .in-. stant normal 'speed of the'engine is restored lever 42 breaks contact with screw 46, cansing current by way' of wire 9 todoublejn strength and wheel 16 to be instantly released from thegrasp of magnet 15 by destruction of magnetic attractionbefore explained. Weight 18 is therefore free to move wheel 16 in the opposite direction, subject to arrest of this action the instant magnet 15 again grasps wheel 16 by reason of lever 42 falling into contact with screw 46. A mother form of speed con troller which may be used with the apparatus last descrlbedis shown in Fig. 17. By this arrangement pulley Z from connec'tion with the engine to be regulated communicatesmotion to sha'tt 20, thereby causing levers 50 to be thrown outward in proportion tospeed. Levers 50 are attached to the sleeve 21, bearing upon' disk 23. Above and below disk 23' is a'sezics'ofv carbon plates 24 and 251 Levers 50 should be so adjusted that while the engine is of normal speed the'curreut flowing from binding post I to disk 23, thence to the apparatus by way of wires 9 and 13 will have substantially equal force, thereby checking movement of rib wheel 16.- If speed of the engine increases beyond normal rate, disk 23 bears with increased pressure upon carbou plates-25 and with less pressure upon plates 24. This strengthens the current flowing-from bindtoo ing-post F through wire 13 and weakens that flowing from same source through wire 9, thereby producing increased magnetic attraction and causing wheel l6 with regulating valve attached to be moved by revolving magnet 15 in the rig-ht direction to close the valve.

if speed of engine declines below normal rate spring 26 attached to levers 50 draws disk 23 upward causing plates 24 to receive 5 increased pressure and plates 25 diminished pressure. This has the effect of increasing current through wire 9 and diminishingthatthrough-wire 13, thereby destroying magnetic attraction of magnet 15 and allowing weight 0 '18 to move wheel 16 in the opposite direction to open the valve.

A speed controller with two levers 42 may be used, if desired, for reasonsexplained in separate sleeves which are moved independthe description of Fig. .6. 3y arrangement shown in Fig. 19 the arms 50 connect with ver 42 into contact with screw 46 and diminug tion of speed causes the left hand arm to move left hand lever 12 into contact with screw 45. If the apparatus is used in ships where it would be subject to the disturbing in fiuence of violentmotiomaspeed controlleryvith fans may be substituted for levers'actuated by ecu.-

trifugal force.

Anarrangement of the'above kind is shown in Fig. 18 consisting of ajdisk 50 carrying ahgularly adj usted fans y which heat the air in this specification maybe applied to variwhen set in motion by pulleyZ andcause disk to slide upon shaft 20 against the tension of spring 26 which has tendency to move said' disk in the opposite direction. The disk 50 is in operative contact with lever 42 which controls circuits for the apparatus substantially as before described.

The speed regulating apparatus described ous kinds of valve-gear. If used as a throttling governor, sllatt t of either Figs. 14, 15 or 16 is connected to the valve stem 51; Fig. 20, thereby regulating the pressure of steam working the engine. Substantially the same arrangement ma also be used to control the speed of water i heels, by attaching shaft 4 above mentioned to the gate 'ad mitting water ;to the wheel. a I

The apparatus is also adapted to govern the speed of enginesby operating variable cut-off valves. In the arrangement shown in Figs. 21 and 22 the piston rod ,52 is connected to crank on shaft 53. Rod 51 connects the slide valve 56 to eccentric on shaft. 53 in the usual manner. Upon the back of slide valve 56 ride the cut-off valves 57, the position of which relative to the steam ports in the slide valve is regulated by right and left hand screws 58 on rod 59. Rod 59 is movable in the block 60, so that when this rod revolves the screws 58 cause the cut-off valves 57 to approach or recedc from each other according to the'direction of movement. Asa mean's'forimparting reciprocating motion to the cut-off valves, the block 60 is attached to eccentric on crank shaft; 53 by means of rod-62.

The apparatus 'showniiin Figs. 14, 15 or 16 may he used to operatethe variable cut-off gear shown'iu Figs. 21 and 22. In. this case shaft 4 is hollow and loosely tits the end of rod-59 which is square in cross section. Re-

.ciprocating motion is imparted to cut-otT valves 57 by motion of eccentricvO, on shaft 53 and atthe same time when rod '59 revolves to the right or left by motion of wheel 16, valves 57 vary the point of cut-off of steam driving the piston.

-Another form of variable cut off is shown in Figs. 23 and 24, which consists of a slide valve 56 connected to the block 63 situated in Increase raised orjlowered in the link .61 and the travel Y of slide valve 56 attached to said block is increased or diminished, thereby hastening or retarding the cut-elf of steam driving the piston.

The application of my invention is not confined to valves constructed in the menu. herein particularly described. Regulating valves to which this invention may suitably be appliedare of many diflerentoonstructions.

Relating to the state of t'he'art .Automat-ic apparatus designed to regulate amhin-eur be regulated, and mechanism responsive to changes in said current to move the current-- The apparatus described in the foregoing rent commoulyconsi'sts of acurrent-varying- .device through which passes the current 10 varying 'devic ein the right direction to coun teract such changes;

specification diflfers from other apparatus for the same purpose in the means-employed to cause instantaneous connection and discon nection between the currentwarying device and an a'uxiliarymotor by which it is moved in response to incipient changes in the currentto be regulated. j

. Wheel 16 is not permanentlyattached to magnets 15, and' as said'wheel is of small weight, its inertia 'or tendency to resist sudden starting and stopping will be proportionally sm'all. On the other hand,'the' weight. and power- .of magnets 15 maybe largely in creased, thereby causing them to act with great power in cont-rolling the motion of wheel 16, but adding nothing to its weight. Magnets 15 may act in actual contact. with wheel 16.- Therefore by this means the power of their grasp is enormously increased. Magnets acting-in actual contact'would under ordinary conditions destroy accuracy of move ment of wheel 16, by lack of complete dis-. chargeof magnetism after shutting otf the current, but by ditferentinl winding and alternation of the current release of the wheel is effected at; the instant of change of main-current. with the quickness peculiar. to electric" names may be used to help control the movements 7 of wheel 16. This device releases the wheel at the same instant that it' is grasped and moved by revolving magnet 15, and also grasps said wheel at the same instant that it is released by the magnet. This causes wheel 16 to ofier very'little resistance to motion, and at the same time prevents it from overshooting the required movement when set in motion. I

My Patents No. 410,663, of September 10, 1889, and No. 429,333, of June 3, 1890, described a double acting pawl mechanism, driven by eccentrics anguiarly arranged on a driving shaft, capable of'moving the current-varying device twice as fast as ordinary pawl mechanism. Pawls or clutches, however, consume time in springing in and out of engagement with the current-varying device which is moved by them. As commonly arranged they are attracted in one direction by a magnet acting in opposition to a spring or its equivalent whichdraws the pawl in the opposite direction. The spring otfers a fixed resi'stance which must beiovercome by the magnet before the pawl: can be thrown into action. The power of the magnet is therefore wasted in overcoming the fixed opposition of the spring and the tendency of a pawl to act irregularly frornexce'ssive slipping increases rapidly by increasing its speed.

My Patent No. 477,637, of June 28, 1892,described a clutch in constant contact with wheel 16. This arrangement by avoiding the necessity of the pawl being moved in and out of engagement with wheel 16 promotes quickness of action and'lessens waste of power, by allowing the magnet to be adjusted close to the pawl. For satisfactory working, however, by this arrangement it is necessary thatthe magnet and pawl be slightly separated, for

without differential action of current if the magnet, pawl and wheel 16 are in actual contact with each other accuracy of movement of the wheel would e atfected by retention of magnetism after shutting oil? the current from the magnet. Also by the'above arrangement the opposition to be overcome in moving wheel 16 is fixed. It does not vanish or abate at. the instant of action of the controlling current as by the operation described in this specification.

Speed governors now in use comprise two t vpes:governors which throttle and thereby change the pressureof steam flowing to the cylinder in accordance with the load imposed upon the engine; also governors which regulate speed by cuttingotf the steam sooner or later during each stroke of the piston.

In a greater part of the speed governors now in common use, force developed wholly by variations of speed is depended upon to move the valve regulating admission of steam to the engine. Therefore a development of fault in speed is depended upon to develop force to move the valve. Theoretically con.-

sidered this. fault might be reduced to an insignificant tigureby connecting the reguvalve; but this construction is open to the objection of proportionally reducing the force applied to move the regulating valve and alsogreatly increases its tendency to overshoot the exact movement required to bring the engine to speed. For this reason governorsthat are very sensitive are not very-powerful and those that are very powerful are not very sensitive.

The lack of speed regulation is forcibly illustrated by marine engines driving the screw propeller which races violently when the pitching of the ship causes the screw to be partly uncovered. But few speed governors successfully use an auxiliary power to tnove the regulating valve, controlled by a device whichsimply regulates the application of the power. The drop cut-oft", however, applied to the Corliss and other engines of similar type is a familiar example of the successful application of auxiliary power con.- trolled by the governor. By this arrangement an auxiliary power works the valve gear, the speed controller or governor merely acting to determine the length of time during each stroke of the piston that the-cut-otf valve shall remain open; but such acut-ofi is applicable only to engines of low speed. \Vith the modern short stroke high speed engines, thepiston would reach the end of the stroke before the cut-off valve could act.

To secure powerful and accurate action is the object of the invention described in the foregoing specification. The alternating current causes wheel 16 tobe powerfully grasped and instantly released by turns, thereby allowing the apparatus to be driven at a cornparatively high rate of speed without losing control of the regulating mechanism attached to-said wheel. 4

I claim as my invention- 1. In an electric regulating apparatus; the combination of a current-varying device, an electro-magnet with differential winding to govern the movements of said current-varying device, e ectric circuits and a device responsive Lu v-v'intloh; in the current to be regulated to condo action ofsaid magnet, and driving-gears! ee-Io said current-varying device prog'fisswtlj 2. In an electric regoiating apparatus, the combination of a currentvarying device, devices governed by elect ro-magnets with differential windings to regulate'the movements of said currcnt-varyiug device, electric circuits and controllers to cause said magnets to actoppositely by turns and driving-gear to move said cturent-varying device progressively or retrogressively.

varying device, electro-magnets to govern the movements of said current-varying device, a stop-motion device to aid in controlling the movements of said current-varying device,

electric circuits and a main-current controller to cause'said electromagnets and stop-motiondevice to act oppositely by turns and drivinggear to move said curieut-varying'device progressively-or retrogressively.

4. The method of governing the action current-varying apparatus, which consists in simultaneoixsly releasing and actuating said current"- varying appai-atusfby differential ofapower the instant the force-of current conleasing and actuating current-varying appa-j rratus by dilferential power the instant the force of c'u rrent controlled by said apparatus varies from the reqiin'ed degree, and in op posing action-of said current-varying appa- Enwmn. Homes; W. I. TWOMBLY.

5 ratus'by alternation ofsaid power the instant 

